Notebook (also called laptop) computers are lightweight personal computers, which are quickly gaining popularity. The popularity of the notebook computers has especially increased since their prices have been dropping steadily, while maintaining similar performance as their larger siblings (i.e., desktop computers or workstations). One clear advantage of notebook computers is their ease of portability. The lighter weight restrictions require the mobile platform manufacturers to produce images that compete with the desktop models, while marinating an increased battery life.
As more functionality is integrated within mobile computing platforms, the need to reduce power consumption becomes increasingly important. Furthermore, users expect increasingly longer battery life in mobile computing platforms, furthering the need for creative power conservation solutions. Mobile computer designers have responded by implementing power management solutions such as, reducing processor and chipset clock speeds, intermittently disabling unused components, and reducing power required by display devices, such as an LCD or “flat panel” display.
Generally, today's notebook computer display panels consume about ten percent of the total platform power. As a result, the display system power efficiency becomes more important when trying to lower power consumption. The power driving an LCD is usually taken from a laptop power rail (e.g., 3 Volts) which itself is provided by stepping down the battery power (e.g., 8-21 Volts).
The LCD displays, however, may require a stepped up voltage (e.g., around 7 Volts). The stepping down and up of the voltage from the voltage source results in inefficiencies, which may be exasperated when cascaded. For example, the cascaded inefficiency may reach thirty percent in some systems, resulting in significant power loss and shortening of battery life in portable systems.